1. Field of the Invention
The present invention relates to a cartridge such as a disk cartridge for receiving therein in a rotatable manner a disk-like medium such as a flexible disk, a hard disk, particularly, an optical disk, an audio or a video cassette for receiving therein a tape-like medium, or a cartridge for a digital compact cassette, and a method of making a shutter for these cartridges.
2. Discussion of the Related Art
Generally, an information medium such as a disk-like medium (for instance, a magnetic disk, an optical disk or an optical-magnetic disk) or a tape-like medium is received in a casing in a form of a cartridge. The cartridge is used by setting it in a recording/reproducing device.
A conventional recording/reproducing medium has a drawback in that dust is easily deposited during handling which causes it to be easily damaged. Further, it is easily influenced by a change of temperature. Accordingly, a shutter is provided in the cartridge to open and close an opening such as a head insertion opening, a driving shaft insertion opening formed in the casing when it is in use or in non-use.
In a conventional method of making a cartridge wherein the shutters is slidably disposed on the casing to open and close the opening formed in the casing, a plurality of the shutter were successively formed from a metallic sheet. The shutters were connected with connecting portions at adjacent end portions of the shutters, and the connecting portions were cut at the final step of making the shutters. In the conventional method for producing the shutter, the cut portion projected from the end portion of each of the shutters. Accordingly, there were problems that a shutter stroke was determined by the cut portions, and the mounting or dismounting of the cartridge from the recording/reproducing device or the opening/closing movements of the shutter could not be smooth because the projection came into contact with a member such as a shutter opening/closing member in the recording/reproducing device. Therefore, it was necessary to precisely control a position where the projection was cut and also a post-treatment was necessary, whereby the manufacturing process was complicated, productivity was poor and reliability on the movement of the shutter was small.
In a case that the shutter was formed by injection-molding synthetic resin, a gate was formed at an end of the shutter and the gate was cut in a post-treatment so that a trace of the gate was not left on the surface of the shutter. Nevertheless, the cut portion was left projecting beyond the edge portion of the shutter. Accordingly, the same problems as the shutter made of metal took place.